content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2011, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
   * Other names may be trademarks of their respective owners.]
   *
   * --------------------
   * VectorXYDataset.java
   * --------------------
   * (C) Copyright 2007, 2008, by Object Refinery Limited and Contributors.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 30-Jan-2007 : Version 1 (DG);
   * 24-May-2007 : Renamed getDeltaXValue() as getVectorXValue(), and likewise
   *               for getDeltaYValue(), and replaced getDeltaX()/getDeltaY()
   *               with getVector() (DG);
   * 25-May-2007 : Moved from experimental to the main source tree (DG);
   *
   */
  
  package org.jfree.data.xy;
  
  /**
   * An extension of the {@link XYDataset} interface that allows a vector to be
   * defined at a specific (x, y) location.
   *
   * @since 1.0.6
   */
  public interface VectorXYDataset extends XYDataset {
  
      /**
       * Returns the x-component of the vector for an item in a series.
       *
       * @param series  the series index.
       * @param item  the item index.
       *
       * @return The x-component of the vector.
       */
      public double getVectorXValue(int series, int item);
  
      /**
       * Returns the y-component of the vector for an item in a series.
       *
       * @param series  the series index.
       * @param item  the item index.
       *
       * @return The y-component of the vector.
       */
      public double getVectorYValue(int series, int item);
  
      /**
       * Returns the vector for an item in a series.  Depending on the particular
       * dataset implementation, this may involve creating a new {@link Vector}
       * instance --- if you are just interested in the x and y components,
       * use the {@link #getVectorXValue(int, int)} and
       * {@link #getVectorYValue(int, int)} methods instead.
       *
       * @param series  the series index.
       * @param item  the item index.
       *
       * @return The vector (possibly <code>null</code>).
       */
      public Vector getVector(int series, int item);
  
  }
  